I first read these books years ago...and you'll still catch me rereading them!
All of the characters exhibit this strength that really draws you in. Especially Sorcha. The way she handled her situation was amazing to say the least. Also, the Marillier uses Celtic folk tales so subtly it took me a while to catch on(like, wehn I picked up my encyclopedia of mythology xp , but it's still well used). It seemed so real to me it took a while to remember that I wasn't living in Ireland.
As for the writing...it just seems ot flow so easily. The first person point of view is perfect for the story.

Opinions?
I know that there are some people who don't like it( burning_eyes ) so I'm wondering why that is...if you're one of these, please explain crying .